Justin Bieber fever strikes Long Beach Middle School Friday as the teen pop star performs a free and private concert as a reward for students who won a contest by collecting more than 27,000 pounds of food for charity.

Bieber, 16, billed on the cover of People magazine as the "World's Biggest Pop Star," is expected to perform a 20-minute set. No tickets will be sold and no outsiders allowed in.

"This is a private event on private property and no one other than students will be permitted to be on school grounds," said Sgt. Anthony Repalone, Nassau Police spokesman.

Bieber, the Canadian tween heartthrob, caused a near-riot at Roosevelt Field mall in November when he was scheduled to sign copies of his debut album, "My World," at a clothing store.

School officials have said the school will be in lockdown for the concert and only students will be allowed to attend.

Repalone said there will be a police presence at the school and trespassers could face charges.

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"Because of Roosevelt Field mall, we know he has a large following. We want to emphasize that if you are planning to go, you are wasting your time. You will have no opportunity to see him or get close to the school," Repalone said.

Students earned the concert by winning a food-collection contest conducted last year by radio station WXRK-FM, known as "92.3 NOW." The food was donated to Island Harvest.

Bieber is scheduled to perform Saturday on Saturday Night Live. He recently announced his first headlining "My World" tour, which stops at Madison Square Garden on Aug. 31, and released his album, called "My World 2.0," with new songs including the hit "Baby."

Bieber will likely perform Friday in the Long Beach Middle School auditorium, which holds 636 students. The school has 851 enrolled, but school officials have said that enough students opted out for an alternate activity offered by the school off-campus. In November, thousands of young girls turned unruly at a planned Bieber visit to Roosevelt Field that was shut down by Nassau Police.

Prosecutors charged Bieber's manager, Scott "Scooter" Braun, with reckless endangerment and criminal nuisance. Island Def Jam music group Senior vice president James Roppo, who was in charge of the event, was charged with four misdemeanors and one felony, including endangering the welfare of children and obstructing governmental administration. Both have pleaded not guilty.